is this a bug, or am I just confused?

[Joey Hess <joey@kite.ml.org>]

I've just noticed a weird problem with all my packages. Either I'm doing
something wrong, or dpkg-shlibdeps is messed up.

My problem is, if I take any of my packages, remove debian/substvars, and
try to rebuild the package, ${shlibs:Depends} in debian/control will expand
to a null string. But now a debian/substvars has been created, and the next
time I build the package, everything works ok. Except, it turns out that
debian/substvars is getting created after debian/tmp/DEBIAN/control gets
made, so the versions of packages my package depends on are sometimes messed
up.

Example: I upgraded slang0.99.34, which used to have a shlibs file like
this:
libslang 0.99.34  slang0.99.34 (>=0.99.34)

To a new version that has a shlibs file like this:
libslang 0.99.34  slang0.99.34 (>=0.99.38)

The first time I rebuilt my package that depends on slang, it came out
depending on slang0.99.34 (>=0.99.34). I built it again, and now it is
depending correctly on slang0.99.34 (>=0.99.38).

Seems that debian/substvars is always one step behind. Can anyone tell me
what I'm doing wrong?

-- 
#!/usr/bin/perl -pl-                                   # ,,ep) ayf >|)nj,,
$_=reverse lc$_;s@"@''@g;y/[]{A-U}<>()a-y1-9,!.?`'/][} #         Joey Hess
{><)(eq)paj6y!fk7wuodbjsfn^mxhl5Eh29L86`i'%,/;s@k@>|@g #  joey@kite.ml.org